Digital advertising accounts for more than one-third of total ad spending in Canada, eMarketer estimates, at CA$4.58 billion ($4.15 billion) annually. But despite spending all this cash, marketers vary a great deal in how they rate the effectiveness of key digital ad formats and channels, according to a new eMarketer report, “Canada Digital Advertising Scorecard: Marketers Rate Digital Advertising Formats and Channels.”

Mobile Search Advertising Effectiveness Scores for Select Marketing Objectives According to Brand and Agency Executives in Canada, April 2015 (scoring based on A+ through F scale)

To find out more, eMarketer asked 18 brand and agency executives in Canada to rate the effectiveness of several digital ad formats and channels: online display, search, digital video, paid social media, mobile search and mobile display. We also asked for opinions on programmatic advertising.

Executives were asked to grade each format or channel on its effectiveness in achieving the following marketing objectives: engagement, lead generation, brand awareness, website traffic, targeting, return on investment (ROI) and sales/transactions, on a scale from A to F. We then calculated an average grade for each format or channel to get a sense of how each performs overall, across multiple objectives.

Search was the best rated of the digital advertising formats, a reflection of its maturity, reliability and measurability. As a derivative of desktop search, mobile search also rates highly among marketing executives, even though it’s far less mature as an advertising channel. Search’s familiarity, due to its use on the desktop, helped bump up mobile’s score, but there are some other reasons too. Unlike mobile display, where the size of mobile phone screens makes it hard to avoid a distracting user experience, mobile search’s text-based results perform very well on small screens. And the smaller screen means that although there are fewer results, the ads that do appear have greater impact.

ROI for mobile search was rated an A- by marketing executives, a reflection of the medium’s cost certainty and its potential to lead to sales and transactions (which was rated a B). Lead generation and targeting also scored well, with B+ marks. Below-average scores were given for mobile search’s ability to create engagement and brand awareness.

“On mobile search you’re looking for something very quickly, like directions or location,” said Naveed Ahmad, CEO of Addictive Mobility. “But you’re probably not going to do mobile search to look for a brand and do a lot of your shopping.”

The singular focus of mobile search contributed to its relatively high ranking, which should only increase in the future as the mobile search experience continues to improve. Respondents identified several areas of improvement.

“When people are on mobile they have a tendency to engage quite a bit less,” said David Alexander, manager of integrated marketing at Maple Leaf Foods. “For example, in our business we see the bounce rate quadruple for mobile paid search vs. desktop.”

In addition to the inherent challenges presented by mobile, advertisers didn’t do themselves any favors in their initial attempts to provide a compelling mobile search experience. Mobile-optimized landing sites are still not the norm, and dealing with a hard-to-navigate site can spoil a user’s experience and lead to prolonged disengagement with a brand on mobile.

And mobile ads often fail to take full advantage of smartphone features. “I think advertisers are not taking into account that users are on the kind of device that can make a phone call, that can send a text message, that can bookmark and forward something,” said Veronica Holmes, president of digital at ZenithOptimedia Canada. “They’re not using the capabilities of the device that the search is [being performed] on, and therefore, they miss opportunities.”